1. Field of the Invention
This invention relates to Schottky diodes, and in particular to a polycrystalline silicon Schottky diode array of particular utility for use in fabricating read only memories and programmable logic arrays.
2. Prior Art
Schottky diodes are typically fabricated in monocrystalline silicon together with other electronic components, for example, transistors. In such prior art structures, an N conductivity type buried layer typically has been the diode cathode. Unfortunately, the resulting diodes have high resistance and buried layer to substrate capacitance. Schottky diodes have also been fabricated on polycrystalline silicon. One such approach is described in our copending U.S. patent application Ser. No. 227,837, filed Jan. 23, 1981, and entitled "Low Resistance Schottky Diode on Polysilicon/Metal-Silicide". According to that approach, a plurality of diodes may be fabricated in a single strip of polycrystalline silicon by forming regions of metal over the polycrystalline silicon. A cathode pick-up serves to connect between the surface of the structure and an underlying region connected to the cathodes of the diodes. One disadvantage of the invention described in the above-referenced patent application is the large amount of wafer surface area required for the fabrication of each diode.